Hey Darwin, yes they can get pretty crusty on the backside of the butterfly valve. I found it easiest to remove the TB assembly, 4 nuts and a couple connectors and some hoses should have it off so you can get all the stuff caked on the back side from the PCV valve. These are always a mess on most cars, once clean it should eliminate the codes and idle issues. That oil vapor makes a nasty mess over time and sticks things up.
On these later 'fly by wire' throttle setups the ECU controls when to open the throttle, so bench cleaning is the best way, and least hassle. Pretty common on anything 06 and newer these days.